Missing high effects above 15khz is a common problem with some MP3 encoders. This doesn't sound like distortion, though, it just sounds like less sparkle.

Missing low effects below 60hz shouldn't be because of the player. I know these players are capable of delivering frequencies that low, with a flat frequency response. I've verified this with direct spectrum analysis of the output waveform. And MP3 encoding will not remove those frequencies, so it's not your encoder.

HOWEVER, you must realize (as I said before in this thread) that the empeg player is EQ'd very flat compared to most consumer CD players. Consumer CD players often have their bass artificially boosted out-of-the-box. The empeg doesn't. Perhaps it's just a question of turning up the bass.

Are you sure MMJB is ripping your CDs properly, using DAE? Or is it ripping from the analog audio outputs of the CD player?